PDCCH Reencoding Filter for Invalid Candidate Detection

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Solution Overview

Problem

Current techniques for multi-UE testing systems face challenges in reducing latency and computational resources due to the computationally intensive process of PDCCH blind detection, leading to unnecessary messaging and increased burden in message passing between special-purpose and general-purpose processors.

Innovation Solution

The method involves decoding and reencoding PDCCH signals to calculate detection and channel decoding error probabilities, determining a bit mismatch ratio, and discarding invalid signals based on a threshold, thereby reducing the number of invalid PDCCH candidates before RNTI demasking and CRC checking, which conserves resources and improves detection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PDCCH blind detection is performed using conventional techniques, then all PDCCH candidates are processed through RNTI demasking and CRC checking, but this results in increased computational resources consumption and messaging overhead between processors

Engineering Contradiction:
ImprovePDCCH detection reliabilityVSAvoidcomputational resources consumption
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing channel decoding and reencoding operations before the conventional RNTI demasking and CRC checking steps. A bit mismatch ratio is calculated and compared against a threshold to identify and discard invalid PDCCH candidates early in the processing chain, before they consume additional computational resources in subsequent validation stages. This preliminary filtering action prevents wasted processing on invalid candidates.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and removes invalid PDCCH candidates from the processing stream by discarding them based on the bit mismatch ratio threshold criterion. This extraction of harmful elements (invalid candidates) occurs before they can propagate through the full processing pipeline, reducing the burden on downstream processing stages and minimizing messaging overhead between special-purpose and general-purpose processors.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If all PDCCH candidates are processed through complete validation including RNTI demasking and CRC checking, then detection accuracy is maintained, but latency increases due to processing all candidates including invalid ones

Engineering Contradiction:
ImprovePDCCH detection accuracyVSAvoidprocessing latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary filtering of invalid PDCCH candidates using channel decoding and bit mismatch ratio calculation before the time-consuming RNTI demasking and CRC checking operations. This preliminary action identifies and discards invalid candidates early, so that only valid candidates proceed to the complete validation process, thereby reducing overall processing latency while maintaining detection accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by performing only the necessary channel decoding and reencoding operations to calculate the bit mismatch ratio for filtering purposes, rather than performing the complete validation sequence on all candidates. This partial processing approach is sufficient to identify invalid candidates for discarding, avoiding the excessive processing that would occur if full validation were applied to all candidates including invalid ones.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If channel decoding and reencoding are performed for every PDCCH candidate to calculate bit mismatch ratio, then invalid candidates can be filtered, but computational overhead increases

Engineering Contradiction:
ImprovePDCCH detection efficiencyVSAvoidcomputational overhead
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent introduces an intermediary metric - the bit mismatch ratio calculated from channel decoding and reencoding operations - that serves as a low-cost filter before the more computationally intensive RNTI demasking and CRC checking. This intermediary calculation provides a efficient gating mechanism that prevents invalid candidates from consuming additional computational resources in subsequent stages, improving overall detection efficiency while managing computational overhead.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4451587A1Channel reencoding to reduce invalid physical downlink control channel signals
Publication Date: 2024.10.23 VIAVI SOLUTIONS INC(US)
  • EP4451587A1 patent drawingFigure 1A
  • EP4451587A1 patent drawingFigure 1B
  • EP4451587A1 patent drawingFigure 1C

AI summary

A device may receive a PDCCH signal, may decode encoded bits of the PDCCH signal to generate coded bits, may reencode the coded bits, and may calculate a detection error probability of each coded bit at an output of soft demodulation. The device may calculate a channel decoding error probability that cyclic redundancy check bits are still attached to the coded bits, and may calculate an error probability of channel reencoding, of each coded bit, due to error propagation of polar decoding and reencoding. The device may calculate a probability density of a BMR associated with the coded bits, and may calculate a threshold based on the detection error probability, the channel decoding error probability, the error probability of channel reencoding, and the probability density of a BMR. The device may determine that the PDCCH signal is invalid based on the BMR being greater than the threshold.